This invention relates to apparatus for the medical drainage of the pleural or thoracic cavity, i.e., what is known as chest drainage.
Chest drainage devices have long been used following chest surgery or wounds and also in the treatment of other pleural conditions requiring the fluids be drained from the pleural cavity or so-called space.
Chest drainage may be carried out with or without the application of suction but it is desirable to provide any chest drainage device with the capability of applying a negative pressure to the pleural space, i.e., aspiration, to promote drainage.
When using any type of chest drainage apparatus, extreme care must be taken to prevent the chest drain from communicating to atmospheric pressure, as this can result in lung collapse or other complications with fatal consequences. Therefore, it has been known to provide chest drainage devices with a liquid filled chamber into which the chest drain will extend so that the lower end of the drain is always under the liquid level.
Typical of arrangements having one end of the drain immersed in fluids are Kurtz et al U.S. Pat. Nos. 4,015,603 and 4,261,362, Dodge U.S. Pat. No. 4,085,751 and Tibbs U.S. Pat. No. 3,750,962. Other approaches rely upon the application of suction to the apparatus to prevent normal atmospheric pressure from being permitted to communicate with the drain. Thus, for example, reference is made to Bidwell et al U.S. Pat. Nos. 3,363,626 and 3,363,627, Fertik et al U.S. Pat. No. 3,768,478, Schachet U.S. Pat. No. 3,861,390 and Kurtz et al U.S. Pat. No. 4,112,948 as typical of this approach. Some of these patents employ a chamber in which liquid is placed and to which is connected the chest drain.
However, an important failing of all of these prior apparatuses is that they do not adequately protect a patient if the unit is tipped over, as may readily occur in a hospital, recovery or operating room where there are many person who may kick or otherwise bump the device. The above cited Dodge patent proposes a bucket-like drainage device which is resistant to sloshing or tipping having a liquid seal chamber into which the chest drain extends and configured to at least reduce the flow of liquid from the liquid seal chamber if there is such sloshing or tipping. However, nothing protects the patient from the full application of negative pressure from a vacuum source if there is such spilling, even though the liquid seal might, under some circumstances, be preserved. Also, spillage could result in collected drainage fluid being drawn up into the suction source and, therefore, if there is any tipping, a problem always results. Furthermore, the Dodge apparatus does not include an integral provision for establishing a predetermined pressure to be applied to the drain.
Thus, none of the chest drain devices of the prior art adequately protect a patient in the event the unit is tipped or placed on any of its sides. Other problems are typical of the prior art, including impossible or difficult emptying of the collection chamber without first breaking the liquid seal. Additionally, some previous chest drain devices have used a collection chamber prior to a liquid seal and this is viewed by some medical authorities as creating an undesirable or possibly hazardous large dead air space at the point of entry of the drain into the device. Another problem of some prior art devices has been the result of multiple collection chambers which allow the collected fluid to spill from one chamber to another, not only making measurement of the collected fluid more difficult but also changing the liquid seal and varying the negative pressure which is developed in the drain during aspiration by the device.
It is an object of the present invention to provide a chest drainage unit which includes a liquid safety seal chamber for maintaining constant protection for the patient, not only assuring that the liquid safety seal will not be broken should the unit be tipped over in any direction but also allowing operation to continue even if the unit remains tipped over i.e, is tip-safe.
It is also an object of the invention to provide such a chest drainage unit which prevents contamination of the liquid seal in the event of accidental tipping and causes the level of the liquid to remain relatively constant in relation to the drain point of entry into the chamber.
A related further object of the invention is the provision of such a chest drainage unit which allows the continued level of negative pressure to be maintained in the event of tipping of the unit, regardless of direction, as well as ensuring against the possibility that a high suction pressure would be applied to the patient.
Another object of the invention is the provision of such a chest drainage unit which is emptiable during use without breaking the liquid seal permitting collected fluid to be drained from the unit during usage, as well as providing for accurate measurement of the drainage fluid collected.
It is an object of the invention to provide a liquid drainage which eliminates the large dead air space characteristic of some device of the prior art, i.e., a large air space communicating with the chest drain.
Another object of the invention is the provision of such a chest drainage unit which avoids objectionable spillage of collected drainage fluids in the event of the unit being tipped over in any direction, as well as one which avoids the spillage of fluid from one collection chamber to another.
Other objects of the invention include the provision of such a chest drainage unit which is configured for permitting normal operation to continue in the event the unit is tipped over, at least for a limited time, as well as permitting drainage operation to proceed normally when the unit is once more returned to an upright condition; the provision of such a unit which is smaller than chest drainage devices of the prior art; which is of unitary construction; which can be readily and inexpensibly molded of impact resistant synthetic resin materials; and which incorporates no moving parts or objectable valves, check mechanisms or the like.
Other objects will be in part apparent and in part pointed out hereinbelow.